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Abstract: The structural and electrical properties of infinite-layer CaCuO2 (IL CaCuO2) under high pressure at room temperature were studied using a diamond anvil cell by in situ high pressure energy-dispersive X-ray diffraction with synchrotron radiation and by simultaneous resistance and electrical capacitance measurements. The results indicate that the primary crystal structure of IL CaCuO2 is stable under pressure up to 30GPa with an anisotropic compressibility. The equation of state of IL CaCuO2 was obtained from the V/V 0−P relationship based on the Birch–Murnaghan equation, which gives rise to a bulk modulus B 0=96GPa in the low pressure range below 6GPa, and B 0=186GPa at pressures from 6 to 30GPa for IL CaCuO2. The resistance and capacitance measurements of IL CaCuO2 up to 20GPa revealed several unusual changes. There is an abrupt resistance drop in the pressure range of 3–6GPa followed by an abnormal hump occurring around 12GPa with increasing pressure. Corresponding changes were also observed in the dependence of capacitance on pressure. The former drop is attributed to an isostructural phase transition as observed in the synchrotron radiation experiments. The latter is considered to be related to an electronic structure transition resulting from the anisotropic compression of the IL CaCuO2 unit cell under high pressure. [Copyright &y& Elsevier]

Studies a series of non-linear optically active bis(benzylidene)ketones by electron crystallography. Failure of the method because packing-energy calculations are not sufficiently sensitive; Refining the approximate model with SHELXL; Superior data set obtained at 300 kV with online data acquisition.

Aim: To examine the accuracy of optical biopsy (OB) using elastic-scattering-spectroscopy (ESS) to determine the histological status of axillary lymph nodes in breast cancer and pigmented skin lesions. Methods: The OB-ESS system utilizes the differential absorption and scattering properties of light, which is sensitive to the morphological changes in malignant tissue. It consists of a xenon arc lamp, optical fibers, spectrometer and a computer. The OB-ESS system was used to obtain optical spectra from axillary lymph nodes and pigmented skin lesions, and the results analysed by linear discriminant analysis (LDA). Histology on the tissues was compared with the optical biopsy results. Results: Optical spectra were obtained frown 327 axillary nodes in 136 patients with breast cancer, and the system could discriminate between positive and negative lymph nodes with an accuracy of 81% (sensitivity 69% and specificity 85%). On testing a subset of lymph nodes with near total metastasis, the accuracy increased to 96% (sensitivity 70% and specificity 99%). 93 pigmented lesions from 74 patients were sampled, and optical biopsy distinguished melanoma from benign naevi with a sensitivity, of 91% and a specificity of 79%, and melanoma from dysplastic naevi with a sensitivity of 92% and a specificity of 79%. Conclusion: In testing axillary nodes, optical biopsy has similar accuracy to frozen section and touch imprint cytology. In pigmented skin lesions, OB was more sensitive, but less specific than clinical examination by an experienced dermatologist. Its results are almost instantaneous and it does not require a skilled operator. [ABSTRACT FROM AUTHOR]

STEM image simulation is achieved via hybrid CPU/GPU programming under parallel algorithm architecture to speed up calculation on a personal computer (PC). To utilize the calculation power of a PC fully, the simulation is performed using the GPU core and multi-CPU cores at the same time to significantly improve efficiency. GaSb and an artificial GaSb/InAs interface with atom diffusion have been used to verify the computation. [ABSTRACT FROM AUTHOR]

Oxygen vacancy (V O ) ordering and its mobility in YMnO 3 have been studied via electron-beam irradiation. By controlling the beam intensity, three commensurate (A, B and C-type) and one incommensurate V O -orderings can be formed. The transformation from the A-type to the C-type ordering has also been revealed, which could be attributed to the migration of V O from the apical V O site to the planar V O site. Further, intense irradiation can introduce more V O s and make a breakdown of the ferroelectric displacements of Y ions. These results suggest that the V O s in YMnO 3 system are highly active in several ordered ways and also have a high mobility. [ABSTRACT FROM AUTHOR]

Herein we report an example of x CoFe 2 O 4 /(1 − x )BaTiO 3 composites formed in 0-3 type structure, which exhibit abnormal magnetic field-dependent magnetoelectric behaviors different from those reported previously. The magnetoelectric response of the composites with x ≤ 0.4 is found to undergo a minor change upon the dc bias magnetic field. However, when the BaTiO 3 content is decreased to the extent x = 0.5, the magnetoelectric response exhibits a staircase-like dependence on the dc magnetic field with a sudden decrease at around 2.5 kOe. We propose another possible mechanism to explain the field-dependent magnetoelectric behaviors of our CoFe 2 O 4 /BaTiO 3 composites. [ABSTRACT FROM AUTHOR]

Highlights: [•] We synthesized the Sr2CuO3.4 superconductor with a new La214 type modulation structure. [•] The new modulation structure shows superconducting transition with Tc 48K. [•] The new modulation structure is related to the distribution of apical oxygen, of Pmmm symmetry. [ABSTRACT FROM AUTHOR]

Abstract: Pure single crystal tubes formed from C60 molecules, with a face-centered cubic (fcc) structure were fabricated by a liquid–liquid interfacial precipitation method using C60 powder. A bulk transition from fcc to a simple cubic structure and a surface transition from (1×1) to (2×2) have been observed around 246K (bulk transition temperature T B) and 214K (surface transition temperature T S), respectively, during the measurement of the temperature dependence of electrical resistance. The initiation of the two transitions under pressure was investigated using a piston cylinder high pressure apparatus and it was found that both T B and T S increase with increasing pressure. And the C60 molecules at the surface of the tube exhibit the same behavior of that in the bulk at a pressure of about 2.1GPa. [Copyright &y& Elsevier]

Abstract: This paper investigates the structural and magnetic properties of hexagonal Ba(Ti1−x Fe x )O3−δ (x=0.3 and 0.7) ceramics, synthesized with solid-state reaction method. Transmission electron microscope investigations reveal that structural phase separation featured by non-modulated and modulated phases is identified by the electron diffraction patterns taken along [001] zone axis in x=0.3 sample (BTF30). While for x=0.7 sample (BTF70), a pure phase with commensurate and incommensurate modulations at different directions is identified. The superstructure peaks observed in their X-ray diffraction patterns are verified by their individual commensurate modulation, q s=1/2 (31-2) in the modulated phase of BTF30 and q 4,−1=4/9(304)–(001) in BTF70. In addition to the room-temperature weak ferromagnetism of BTF30 and paramagnetism of BTF70, spin glass transitions with T f=3.4K for the former and T f=33.6K for the latter are observed. On the basis of the structural characteristics, the influence of O1 and O2 vacancies on magnetic and dielectric properties of the doped system is discussed. [Copyright &y& Elsevier]

Abstract: The BaIr1− x Mn x O3 (0.0≤x≤1.0) solid solutions were synthesized by using the solid-state chemical method and high pressure sintering in the pressure range 0–5GPa. According to the pressure–composition “phase diagram” at 1000°C, the 9M BaIr1− x Mn x O3 transforms to the 6M form at 5GPa and x≤1/6. In the x range 0.5–1.0, it transforms to the 9R form in a large pressure range. For the 9M BaIrO3, the Mn ions substitution for Ir ions enhances the semiconducting property, and reduces the weak ferromagnetism. When x is larger than 1/3, the 9M/9R BaIr1− x Mn x O3 behave spin–glass-like state at low temperature, with the glass transition temperature T g about 60K. For the 6M BaIrO3, the Mn ions doping results in that it transforms to insulator and spin–glass-like magnetism from the initial paramagnetic metal. [Copyright &y& Elsevier]

Abstract: The high-pressure in situ angular dispersive x-ray diffraction (ADXD) study on the zinc blende (ZB) type ZnSe nanoribbons were implemented using image-plate technique and diamond-anvil cell up to about 32GPa. The pressure-induced structural transition from the ZB to a rocksalt (RS) type phase occurs at about 12.6GPa, and the relative volume reduction at the transition point is close to 13%. Moreover, the variation in the relative volume with pressure seems discontinuous at about 5.5GPa, which indicates an unidentified transition. The bulk modulus B 0 for the ZB and RS phases were determined through fitting the relative volume–pressure experimental data by Birch–Murnaghan equation of states. High-pressure Raman scattering experiments revealed that the transverse optical (TO) phonon mode splits into two peaks at about 5.5GPa, which is compatible with the result of ADXD. The disappearance of the longitudinal optical peak above 13GPa is due to the semiconductor–metal transition. Surprisingly, all Raman scattering peaks begin to become broad from the lower pressure (5–6GPa) relative to the bulk ZnSe (normally ∼11GPa), and the corresponding TO phonons become invisible beyond 14.7GPa. Using the values of the bulk modulus from ADXD experiments, the corresponding mode Grüneisen parameters can be obtained for the ZB phase. [Copyright &y& Elsevier]

• A new model is developed to analyze and predict lifetimes of cyclic creep curves in concrete. • Fatigue damage evolution of plain and fiber-reinforced concrete is described by Weibull distribution function. • Sparks-Menzies equation is explained as an inherent property of normalized damage evolution. • Reliable lifetime prediction is possible even from premature interruption of fatigue test. A phenomenological approach is proposed to describe and predict the random behaviour of the total strain in plain and fiber concrete under compressive fatigue loading. Twofold viewpoints are considered in the assessment of the fatigue damage process. The first one, acknowledged as the stochastic cumulative damage evolution in terms of the number of applied cycles is represented by a sample function, physically identified with the total specimen strain caused by matrix microcracking. The second one is ascribed to the intrinsic scatter of the total lifetime referred to as the prefixed ultimate fatigue strain limit state (not necessarily failure). The sample function, once normalized to the total fatigue lifetime, is identified as a cumulative distribution function (cdf) of the generalized extreme value (GEV) family, particularly as Weibull distribution. Besides the reliable probabilistic lifetime prediction for the material under compressive fatigue, the approach allows fatigue tests to be prematurely interrupted while the remaining evolution of the ε-N curve up to failure is fully restored from the fragment recorded. In this way, a remarkable time and cost reduction of the experimental program is achieved without detriment of data reliability. [ABSTRACT FROM AUTHOR]

The size effect on the compressive fatigue behaviour of fibre-reinforced concrete is herein studied by testing cubes of 40 mm, 80 mm and 150 mm in edge length. Even though the compressive strength resulted the same in the three cases due to the ductility of the material in this range of sizes, the size effect was evident on the fatigue response of the 40-mm specimens, which reached numbers of cycles up to three orders of magnitude higher than expected. Furthermore, the mean residual strength of run-out specimens of this size increased by 42% due to the cyclic loads. Regarding the fatigue creep of the material, the logarithms of the secondary strain rate and the number of cycles to failure presented a linear relationship that is size-independent and can predict the fatigue life of run-out specimens. Meanwhile, the strain upon failure decreased with the increase of size although the crack patterns were still similar. • Increased fatigue life for smaller cubic specimen sizes of fibre-reinforced concrete. • Constant compressive strength under the size of 150 mm due to the effect of fibres. • Mean increment of a 42% in the post-fatigue compressive strength of run-out specimens. • Size-independent relationship between the secondary strain rate and fatigue life. • Decrease of fatigue failure strain for larger sizes. [ABSTRACT FROM AUTHOR]

The occupation of Zn ion in (Fe 1-x Zn x) 2 Mo 3 O 8 was investigated by many experimental analysis methods and theoretical calculations, but the corresponding direct observation has not yet been reported so far. In this work, it is confirmed that the Zn ion prefers to occupy the tetrahedron position in the FeZnMo 3 O 8 by using scanning transmission electron microscopy. Besides, the (Fe 0·75 Zn 0.25) 2 Mo 3 O 8 shows ferrimagnetism by doping Zn ions, and the valence of Fe ions remains +2 indicated by the X-ray photoelectron spectroscopy results. • Direct experimental evidence for the occupation of Zn ions in the tetrahedron sites in FeZnMo 3 O 8 is displayed. • The valence state of Fe ions in Fe 2 Mo 3 O 8 and (Fe 0.75 Zn 0.25) 2 Mo 3 O 8 is indicated. [ABSTRACT FROM AUTHOR]

Abstract: The high-pressure phase of iridium-based compound Ba3CaIr2O9 was synthesized using high-pressure sintering. Being different from the distorted hexagonal BaTiO3 structure of the ambient Ba3CaIr2O9, the high-pressure phase crystals into the 1:2 B-site-ordered perovskite structure with the space group P-3m1 (Z=1). Through fitting the X-ray powder diffraction (XRD) data with Rietveld analysis, in which the obtained R p, R wp, and R exp factors are 7.49%, 11.4%, and 4.82%, respectively, the lattice parameters are a=5.8296(1)Å and c=7.1659(2)Å. The atomic coordinates and the main interatomic distances and bond angles were also obtained. The relationship of electrical resistivity versus temperature shows that the high-pressure phase of Ba3CaIr2O9 is a semiconductor in the temperature range of 5–300K. The measurement of temperature dependence of magnetic susceptibility indicates that it is paramagnetic. [Copyright &y& Elsevier]

Abstract: We investigated the effect of uniaxial and hydrostatic pressure on resistivity and ac-magnetic susceptibility of two-dimensional layered manganite, La1.25Sr1.75Mn2O7 (LSMO125) to investigate the lattice effect on magnetic and electronic properties. Asymmetric role of uniaxial pressure, || and ⊥ to c-axis on the spin flop and charge transport has been revealed while comparing hydrostatic pressure. Uniaxial pressure along c-axis increases metal–insulator transition temperature (T MI) and ferromagnetic ordering temperature (T C), whereas it decreases the resistivity along ab-plane (ρ ab). In contrast to pressure along c-axis, T MI and T C decrease, whereas the resistivity along c-axis (ρ c) increases with pressure || to ab-plane. ρ c/ρ ab is quite large, increasing with pressure and shows a peak at around T MI. Uniaxial pressure behaviour is strongly related to the Mn–O–Mn linkage between MnO2 layers and the spin reorientation from the apical axis to the basal plane and vice versa with pressure. Both ρ ab and ρ c decrease whereas T MI and T C increases under hydrostatic pressure. Influence of spin and charge on magnetic and electrical properties under hydrostatic pressure are explained by pressure-induced cant between the MnO2 bilayers and variation in bond lengths. The different pressure driving rates of T MI while measuring ρ ab and ρ c confirms that there is a strong competition between the in and out plane components under hydrostatic pressure. [Copyright &y& Elsevier]

Abstract: In this paper, electron diffraction (ED), high-resolution transmission electron microscopy (HRTEM), and theoretical simulations have been used to study the room-temperature structure of the multiferroic BiMnO3 synthesized under high pressure. The electron diffraction data reveal that BiMnO3 crystallizes in the centrosymmetric C2/c structure, not in the non-centrosymmetric C2 structure. This is confirmed by further calculations of ED patterns and HRTEM images. The present work is very important for the further studies of BiMnO3. [Copyright &y& Elsevier]